Spark capture system for use with cutting torch

ABSTRACT

A spark absorbing system for use with a cutting torch, comprises a cap having at least one spark opening therethrough and a spark capture unit coupled to the cap and positioned to capture sparks passing through the spark opening. The spark capture unit may comprise a tube extending from the cap and may include an outlet and a flow-reduction element positioned between the cap and the outlet and/or a spark accumulator between the cap and the spark capture unit. The flow-reduction element may comprise at least one baffle, screen or mesh. The spark absorbing system may further include a spark ramp extending from the cap opposite the spark capture unit and/or a shield, which may define a cutting space between the shield and the cap.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application that claims priority toU.S. application Ser. No. 15/952,903, filed Apr. 13, 2018, which is anon-provisional application which claims priority from U.S. provisionalapplication No. 62/485,483, filed Apr. 14, 2017, which is incorporatedby reference herein in its entirety.

TECHNICAL FIELD/FIELD OF THE DISCLOSURE

The present disclosure relates generally to an apparatus and method forcontaining sparks emitted during a cable cutting process. Moreparticularly, the present disclosure relates to a spark capture systemfor use with a cutting torch.

BACKGROUND OF THE DISCLOSURE

Cutting torches are frequently used to cut metal, including metalcables. Some of the applications in which it may be desired to cut metalinclude, but are not limited to, concrete members that may includetensioning strands, rebar, or the like.

Many structures are built using concrete, including, for instance,buildings, parking structures, apartments, condominiums, hotels,mixed-use structures, casinos, hospitals, medical buildings, governmentbuildings, research/academic institutions, industrial buildings, malls,bridges, pavement, tanks, reservoirs, silos, foundations, sports courts,and other structures.

Prestressed concrete is structural concrete in which internal stressesare introduced to reduce potential tensile stresses in the concreteresulting from applied loads; prestressing may be accomplished bypost-tensioned prestressing. In post-tensioned prestressing, a tensionmember is tensioned after the concrete has attained a specified strengthby use of a post-tensioning tendon. The post-tensioning tendon mayinclude anchors, the tension member, and sheathes or ducts. A tensionmember is conventionally constructed of a material having sufficienttensile strength that can also be elongated. Tension members areconventionally formed from a strand and a sheath. The strand isconventionally formed as a single or multi-strand metal cable. Thestrand is conventionally encapsulated within a polymeric sheath extrudedthereabout to, for example, prevent or retard corrosion of the metalstrand by protecting the metal strand from exposure to corrosive orreactive fluids. Likewise, the sheath may prevent or retard concretefrom bonding to the strand and preventing or restricting movement of thesheath during post-tensioning. The sheath may be filled with grease tofurther limit the exposure of the metal strand and allow for increasedmobility. The post-tensioning tendon conventionally includes ananchorage at each end. The tension member is fixedly coupled to a fixedanchorage positioned at one end of the post-tensioning tendon, theso-called “fixed-end”, and stressed at the other anchor, the“stressing-end” of the post-tensioning tendon.

The concrete may be poured into a concrete form. The concrete form maybe a form or mold into which concrete is poured or otherwise introducedto give shape to the concrete as it sets or hardens thus forming theconcrete member. The post-tensioning tendon may be positioned within theconcrete form, the concrete poured, and the concrete member thenstressed to form a concrete segment. After the concrete member isstressed, the tension member extends beyond the edge of the concretesegment. In some cases, a pocket former is placed around the strandbefore the concrete is poured, which results in a pocket in the curedconcrete. The end of the strand extends outwardly from the concrete and,if a pocket former was used, the end of the strand extends through andoutwardly from the pocket. Conventionally, at least a portion of thestrand that extends beyond the edge of the concrete member is cut, suchas by a cutting torch. If a pocket former was used, the cutting of thestrand may take place in the pocket.

Cutting torches generate sparks during the process of cutting thestrand. Sparks generated by cutting torches may cause fires in nearbyflammable materials. Such fires may result in damage, danger topersonnel, delays, and increased monitoring costs.

SUMMARY

A spark absorbing system for use with a cutting torch may comprise a caphaving at least one spark opening therethrough and a spark capture unit.The spark capture unit may be coupled to the cap and positioned tocapture sparks passing through the spark opening. The spark capture unitmay comprise a tube extending from the cap. The spark capture unitincludes an outlet and may include a flow-reduction element positionedbetween the cap and the outlet. The flow-reduction element may compriseat least one baffle, screen or mesh. The spark absorbing system mayfurther include a spark accumulator between the cap and the sparkcapture unit, a spark ramp extending from the cap opposite the sparkcapture unit, and/or a shield and generally parallel to the cap so as todefine a cutting space between the shield and the cap.

The cap may comprise one or more layers of mesh screens, which may begenerally parallel.

In some embodiments, a system for cutting a strand in a concrete segmenthaving an end, a pocket at the end, and a strand extending from thepocket may include a cutting torch including a cutting head and a sparkabsorbing system supported on the cutting torch. The spark absorbingsystem may comprise a cap having at least one spark opening therethroughand a spark capture unit that may be coupled to the cap and positionedto capture sparks passing through the spark opening. The spark captureunit may be a tube extending from the cap. The spark capture unit mayinclude an outlet and a flow-reduction element positioned between thecap and the outlet and the flow-reduction element may include at leastone baffle, screen or mesh.

The spark absorbing system may further include a spark accumulatorbetween the cap and the spark capture unit, a spark ramp extending fromthe cap opposite the spark capture unit and positioned to receive sparksemitted at the cutting head, and a shield coupled to the spark ramp andgenerally parallel to the cap so as to define a cutting space betweenthe shield and the cap, with the cutting head in the cutting space.

In some embodiments, a process may include the steps of supplying aconcrete segment, the concrete segment having an end, the concretesegment having a pocket at the end; extending a strand through thepocket; providing a cutting torch having a cutting head and a sparkabsorbing system coupled thereto, the spark absorbing system comprisinga cap having at least one spark opening therethrough and a spark captureunit coupled to the cap and positioned to capture sparks passing throughthe spark opening; placing the cutting head in the pocket; operating thecutting torch; and capturing or deflecting sparks generated from thecutting torch using the spark absorbing system. In some embodiments, thecap may enclose the pocket and the spark absorbing system may extendoutwardly therefrom.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is best understood from the following detaileddescription when read with the accompanying figures. It is emphasizedthat, in accordance with the standard practice in the industry, variousfeatures are not drawn to scale. In fact, the dimensions of the variousfeatures may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1 is a detailed view of a prior art cutting torch.

FIG. 2 is a cross-sectional view of a cutting torch with a sparkabsorbing unit consistent with certain embodiments of the presentdisclosure received in a pocket in a concrete member.

FIGS. 3 and 4 are orthographic views of the cutting torch and sparkabsorbing unit of FIG. 2.

FIGS. 5-7 are each a cross-sectional view of a portion of a sparkabsorbing unit consistent with certain embodiments of the presentdisclosure.

DETAILED DESCRIPTION

It is to be understood that the following disclosure provides manydifferent embodiments, or examples, for implementing different featuresof various embodiments. Specific examples of components and arrangementsare described below to simplify the present disclosure. These are, ofcourse, merely examples and are not intended to be limiting. Inaddition, the present disclosure may repeat reference numerals orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments or configurations discussed.

“Coupled” for purposes of this disclosure, may include any form ofcoupling, including but not limited to “mechanical coupling.”“Mechanically coupled” for purposes of this disclosure, may include, butnot be limited to, threaded couplings, press fitting, mechanicalwelding, chemical welding, friction welding, thermal coupling orwelding, electrical welding, optical welding, or beam-energy welding.

As depicted in FIG. 1, a cutting torch 20 may be used for a cuttingstrand 16. In certain embodiments, cutting torch 20 may be a plasmacutting torch or may use a gas source, such as a source of air,nitrogen, argon or oxygen, and an electrical power source and electrodesto generate a stream of air, nitrogen or other gaseous at temperaturessufficient to cut strand 16, for example and without limitation, fromabout 3,000° C.-5,000° C. or more.

While the present disclosure is presented in the context of use with acutting torch, it will be understood that the spark absorbing systemsdescribed herein can be used advantageously with any strand-cuttingdevice that generates sparks, including but not limited to oxy-cuttingtorches fueled with acetylene, propane, or stabilized mixtures ofmethylacetylene (propyne) and propadiene.

Cutting torch 20 may include a handle 22, a head 24, and a cutting tip26. A heat shield 25 may surround at least a portion of cutting tip 26.Heat shield 25 may be formed of, for example, ceramic. Cutting torch 20may also include a compressor, cylinder or other source (not shown) forthe gas to be formed into the plasma, a source of electrical power (notshown) and an electrode (not shown) for converting the gas into agaseous plasma. The electrode may be disposed in handle 22, head 24, orin another portion of cutting torch 20. In certain embodiments, cuttingtorch 20 may include an electrical ground. The electrical ground mayinclude, but not be limited to a metal or other conductive element thattouches strand 16. In other embodiments, the ground may be clamp 28, asdescribed hereinbelow. A superheated stream of gaseous plasma isdischarged from cutting tip 26. During cutting, cutting tip 26 ispositioned near strand 16.

Clamp 28 may be releasably coupled to strand 16, such as through bracket30. Bracket 30 may be coupled to head 24 of cutting torch 20. Bracket 30may be sized to be friction fitted around head 24 or may be permanentlyattached to head 24 or heat shield 25. In some embodiments, positionersmay be attached to bracket 30 so as to position cutting tip 26 at apredetermined distance from anchor 14 along the longitudinal axis ofstrand 16. In certain embodiments, the positioners may be a pair ofdepending jaws 32, 34. In some embodiments, depending jaws 32, 34 may bepivotally attached to bracket 30 and may be biased towards a closedposition by a biasing mechanism 36, such as a spring clip. Each ofdepending jaws 32, 34 may include a semicircular relieved portion 38 onits inner edge. When depending jaws 32, 34 are closed, jaws 32 may abutjaw 34 and semicircular relieved portions 38 may form a circular openingthrough which the strand 16 may be received. The bottom portion of eachdepending jaw 32, 34 may include a sloping area 41. Sloping area 41 mayserve to force jaws 32, 34 apart when jaws 32, 34 are pushed againsttension a strand 16. Once strand 16 is received within the circularopening, depending jaws 32, 34 may close around strand 16.

When cutting torch 20 is to be used, jaws 32, 34 may be positionedaround the strand 16. Jaws 32, 34 may be biased into a closed positionby biasing mechanism 36. Jaws 32, 34, with head 24 attached pivotallythereto by the bracket 30, may be moved longitudinally along strand 16until depending jaws 32, 34 are in position. Cutting tip 26 may then bepositioned both angularly and longitudinally about strand 16 and anchor14 for cutting the strand 16.

In certain embodiments, strand 16 may be encased by a sheath. Asdepicted in FIG. 1, the sheath has been removed prior to placement ofclamp 28. In other embodiments, clamp 28 may be placed over the sheath.

Referring now to FIG. 2, a concrete segment 10 may be part of a concretemember that is to be post-tensioned. Concrete segment may or may notinclude a pocket 12, which may be formed in the end of concrete segment10. An anchor 14 may be positioned about strand 16. Strand 16 may beheld in place by wedges 18 seated within anchor 14. A tensioning end 16′of strand 16 may extend through pocket 12, if present, and outwardlyfrom concrete segment 10.

A cutting torch 20 is shown in pocket 12. Elements of the cutting torch20 may be located within pocket 12, including, but not limited to, head24, clamp 28, heat shield 25, and cutting tip 26. A gas supply 80 isdepicted as outside pocket 12. As shown in FIG. 2, a spark absorbingsystem 40 may be included with, coupled to, and/or supported by or oncutting torch 20 and portions thereof may also be received within pocket12.

Referring now to FIGS. 3 and 4, in the embodiment shown, spark absorbingsystem 40 may include a cap 42, a strand ground shroud 52, a spark ramp54, a spark accumulator 56, and a spark capture unit 44.

In the embodiment of FIGS. 3 and 4, clamp 28 is replaced with a shield58. Shield 58 is optional and may be omitted or replaced with a clamp 28or other member. Shield 58 may be a single flat piece having a size andshape corresponding generally to the size and shape of the inner face ofconcrete pocket 12. In some embodiments, a notch 59 is provided inshield 58 to facilitate installation of spark absorbing system 40 ontothe strand end 16′. Shield 58 may be generally parallel to cap 42 sothat a cutting space is defined between the shield 58 and the cap 42. Insome embodiments, the shape of shield 58 may correspond to the shape ofpocket 12 and if the anchor is encapsulated in a polymeric encapsulationlayer, shield 58 may prevent sparks from reaching the anchorencapsulation layer.

Cap 42 is optional. Cap 42 may be a barrier, such as a plate or may havea curved or enclosing surface. Cap 42 may be positioned at leastpartially and, in some embodiments, completely within pocket 12, or mayextend across the opening of pocket 12 and abut the outer surface of theconcrete that forms pocket 12. In some embodiments, cap 42 enclosespocket 12 such that a chamber 13 is defined generally by cap 42, thewalls of pocket 12, and either the floor of pocket 12 or, if present,shield 58. Cap 42 may be constructed of metal, ceramic, orheat-resistant plastic, for example, and may include spark opening 43and handle aperture 46 therethrough. Handle aperture 46 may be adaptedto allow handle 22 to pass through cap 42. Thus, cap 42 may engage or becoupled to and/or supported by or on cutting torch 20. If a spark ramp54 is present, cap 42 may also or alternatively be coupled to and/orsupported by or on spark ramp 54. Cap 42 may be formed from one, two, ormore solid pieces, as shown, may be formed from mesh as described below,or may comprise any other structure that reduces the outward flow ofsparks. In embodiments where the concrete member does not include apocket, either shield 58 or cap 42 may optionally extend fully orpartially around the sides of the cutting torch head.

Strand ground shroud 52 is optional. Strand ground shroud 52 forms agrounded electrical (conducting) contact between strand end 16′ and aground. The ground may be provided via the concrete, via the electricalsystems of cutting torch 20, via a dedicated electrical conductor incontact with the earth, or by any other suitable ground.

Spark ramp 54 is optional. If present, spark ramp 54 may be achannel-shaped piece that extends between the shield 58 and the cap 42,on the opposite side of strand 16 from torch cutting tip 26. In thislocation, spark ramp 54 is configured to divert gas and sparks emittedduring the cutting process and direct the sparks toward spark opening43, through which the sparks may enter spark capture unit 44. If sparkramp 54 is omitted, the inner wall of concrete pocket 12 may serve thesame purpose.

Spark accumulator 56 is optional. If present, spark accumulator 56 maybe a chamber adjacent to spark opening 43 positioned such that sparkspassing through spark opening 43 enter spark accumulator 56. In someembodiments, the volume of spark accumulator 56 relative to the size ofspark opening 43 may cause the velocity of gas flowing through sparkabsorbing system 40 to drop, causing particles entrained in the gas flowto fall out and collect on the floor of spark accumulator 56.

Spark capture unit 44 may include an arrester tube 49 that is connectedat one end to spark accumulator 56 and has at its opposite end one ormore outlets 50 that may each optionally be enclosed by a mesh screen48. Spark capture unit 44 may serve to capture and/or deflect sparks,preventing or restricting sparks from exiting pocket 12 through outlets50. Spark capture unit 44 may allow gas from gas source 80 to passthrough outlets 50. In certain embodiments, spark capture unit 44 may bea generally cylindrical or polygonal extension from cap 42. Sparkcapture unit 44 may be releasably attached to or integrally formed withcap 42 or may be releasably attached to or integrally formed withcutting torch 20.

In some embodiments, arrester tube 49 may comprise a hollow tube. Inother embodiments, arrester tube 49 may contain one or moreflow-reduction elements, including but not limited to the exemplaryflow-reduction elements illustrated in FIGS. 5-7. In the embodimentshown in FIG. 5, the flow-reduction element of spark capture unit 44 mayinclude one or more baffles 60. In the embodiment shown in FIG. 6, theflow-reduction element of spark capture unit 44 may include one or moremesh screens 62. In the embodiment shown in FIG. 7, the flow-reductionelement of spark capture unit 44 may include one or more cylinders 70.When spark capture unit 44 includes more than one cylinder 70, cylinders70 may be nested. In some embodiments, one or more of cylinders 70 mayinclude mesh 72.

In still other embodiments, the cap 42 itself may include one or moremesh screens and may, in some embodiments, omit any or all of spark ramp54, spark accumulator 56 and spark capture unit 44. Cap 42 acts tocapture and/or deflect sparks, preventing or restricting sparks frompassing through cap 42. In certain embodiments, cap 42 may comprise aplurality of layered mesh screens.

The foregoing outlines features of several embodiments so that a personof ordinary skill in the art may better understand the aspects of thepresent disclosure. Such features may be replaced by any one of numerousequivalent alternatives, only some of which are disclosed herein. One ofordinary skill in the art should appreciate that they may readily usethe present disclosure as a basis for designing or modifying otherprocesses and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein. Oneof ordinary skill in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

What is claimed is:
 1. A spark absorbing system, the spark absorbingsystem comprising: a cap having at least one spark opening therethrough;a shield, the shield positioned apart from the cap such that a cuttingspace is formed between the shield and the cap; a spark ramp, the sparkramp extending between the cap and the shield; a spark capture unit, thespark capture unit attached to or formed integrally with the cap, thespark capture unit including a spark opening.
 2. The spark absorbingsystem of claim 1, wherein the spark capture unit further includes: anoutlet; and a flow-reduction element positioned within the spark captureunit between the cap and the outlet and wherein the flow-reductionelement comprises at least one baffle, screen or mesh.
 3. The sparkabsorbing system of claim 1, wherein the cap is adapted to engage acutting torch.
 4. The spark absorbing system of claim 3, wherein the capis a plate or a curved surface.
 5. The spark absorbing system of claim3, wherein the spark opening in the cap is adjacent the spark captureunit.
 6. The spark absorbing unit of claim 1, wherein the cap furtherincludes a strand ground shroud.
 7. The spark absorbing unit of claim 1,wherein the shield includes a notch adapted to pass a strandtherethrough.
 8. The spark absorbing unit of claim 7, wherein the shapeof the shield corresponds to the shape of a pocket in concrete.
 9. Thespark absorbing unit of claim 1, wherein the spark ramp extends from thecap and is positioned to receive sparks emitted at a cutting head of acutting torch and wherein the spark ramp is configured to divert gas andsparks emitted at the cutting torch toward the spark opening.
 10. Thespark absorbing unit of claim 1, wherein the spark ramp is channelshaped.
 11. The spark absorbing unit of claim 1 further including aspark accumulator positioned between the cap and the spark capture unit,wherein spark accumulator comprises a chamber adjacent to the sparkopening.
 12. The spark absorbing unit of claim 1, wherein the capcomprises one or more mesh screens.
 13. The spark absorbing unit ofclaim 1, wherein the spark capture unit includes an arrester tube. 14.The spark absorbing unit of claim 13, wherein the arrester tube includesa plurality of baffles positioned within the arrester tube, each baffleextending partially across a diameter of the arrester tube.
 15. Thespark absorbing unit of claim 13, wherein the arrester tube includes aplurality of mesh screens, wherein each mesh screen extends across adiameter of the arrester tube.
 16. The spark absorbing unit of claim 13,wherein the arrester tube includes a plurality of nested cylinderspositioned longitudinally within the arrester tube.
 17. The sparkabsorbing unit of claim 16, wherein one or more of the nested cylindersincludes mesh.